Three summers ago, when Marc Imlay and a small band of volunteers were yanking unwanted plants in a local park, they stumbled across something they had never seen before: a deep green grass with rippling waves across its blades.
In later visits to Little Paint Branch Park in Maryland's Prince George's County, they noticed the grass was quickly blanketing the area. "We knew there was something wrong," said Imlay, conservation biologist with the Anacostia Watershed Society, who gathered samples for botanists to identify.
In late 2006, he got his answer: It was wavyleaf basketgrass, a species native to southeast Asia.
It was first seen in the United States only a decade before-an amateur botanist, Ed Uebel, spotted a few small patches in 1996 in Patapsco Valley State Park, about 20 miles from where Imlay had found it.
Imlay's worries that the plant was not only exotic, but highly invasive, were confirmed last summer when Kerrie Kyde, the invasive plant specialist with the Maryland Department of Natural Resources, revisited Patapsco.
The small patches observed by Uebel now blanketed more than 150 acres. "It is kind of mind-boggling," Kyde said. "It looks like somebody rolled out the Astroturf."
Based on its rapid spread, botanists fear that it could rapidly replace native plants, turning forest floors into monocultures with little habitat value for other species throughout the region.
But instead of wavyleaf basketgrass being the latest invasive species to roll across the landscape-as has been the case with everything from kudzu and mile-a-minute to gypsy moths and snakeheads-Imlay and Kyde think they have a shot at driving the plant from its beachhead in North America.
"So far, it is only found in Maryland," Imlay said. "We have a realistic chance of saving what will otherwise destroy 10 percent of the herbaceous layer of one fourth of the United States."
If that happens, it would be a remarkable accomplishment. Although efforts have succeeded in removing problematic species from local areas, such as parks, examples of removing an invasive species from the continent are rare.
"I'd be hard-pressed to pick one out and point at it," said Alan Tasker, the federal noxious weed coordinator at the U.S. Department of Agriculture's Animal and Plant Heath Inspection Service, which is charged with keeping harmful pests out of the country. "This would be one of the few citable examples."
Right now, the plant has only been spotted in a handful of locations, which also include the Liberty Reservoir and Hernwood Landfill in Baltimore County.
And in one location, wavyleaf basketgrass has nearly been eradicated. Imlay called on volunteers through last summer to help fight back against the plant in Little Paint Branch Park, including at one point assembling an international crew from the World Bank. "I wanted to teach people so they would realize that when something first hits on their own continent, that is the time to get it," he said.
Altogether, Imlay led more than a dozen trips to the park in 2007, with scores of volunteers racking up more than 400 hours spraying and pulling wavyleaf basketgrass, which had spread over roughly three acres. By year's end, they had knocked it back by about 80 percent.
Imlay is seeking volunteers to finish off the plant in the park this spring, and more volunteers are queuing up for the fight. He said the Maryland Chapter of the Sierra Club is pledging 325 volunteer hours toward eradicating the plant.
Meanwhile, members of the Montgomery County "Weed Warriors" are being trained to identify the plant. "This year," he said, "the idea is to scout farther in all directions and remove it where we see it."
Nonetheless, ridding the plant will be no easy task, especially in Patapsco Valley State Park where it already blankets more than a quarter-square-mile of territory.
Kyde said the plant is too widespread to be eradicated in a single year. So, while volunteers will be working to control the plant, other efforts will go into precisely mapping known locations, understanding the plant's biology and determining the most effective herbicides to use against it.
"I suspect this is easily a three-year effort and maybe five," Kyde said. "And I would want to monitor for five or 10 years thereafter."
The maps will help botanists identify-and get rid of-any pockets that spread beyond the boundaries of current patches, thereby containing the invasion.
The plant has two ways to spread. Its stems can grow horizontally along the ground and root at the lower stem nodes. And, when it blooms from mid-September through November, it grows seed-bearing spikelets. The spikelets have long pointed bristle-like awns that produce a sticky substance that readily attaches the seeds to anything which may brush past. "It's about the stickiest thing I've ever come across," Imlay said.
To limit the spread, removal priority is likely to be given to areas along paths, Kyde said. But people may not be the only way to move seeds around. "I believe the deer are a major vector," she added, noting that people have reported seeing deer legs covered with awns and seeds. "That's bad news."
The plant is native to India and Southeast Asia. It is also found in Italy, although it's not clear whether it is native to Italy or was imported, Kyde said.
It's not clear how the plant got to Maryland, but because one of its known locations was near a landfill, Kyde said it's possible the plant was being disposed of, although this particular subspecies is not typically sold in the United States.
Tasker said the USDA is reviewing whether the subspecies should be listed as a noxious weed, which would prevent its importation into the United States and transport across state lines.
While the wavyleaf basketgrass has been in Maryland for nearly a decade, it's still considered an early discovery relative to other species, which are often more widespread before they are noticed. "You often don't find out about it until it is too late to be able to take it out," Tasker said.
He said one of the lessons from the wavyleaf basketgrass experience is the value of citizen efforts, like those by Imlay, who work to control other invasive species in their local area. "Most people don't know their surroundings like they used to," he said. "They don't know what belongs or doesn't belong in an area. They just think, 'Oh it's green, so it's good.'"
As Kyde and Imay work to assemble volunteers, funding-and a plan-to control the plant, it could serve as a model for others of how early detection of an invasive plant, followed by a coordinated rapid response effort, can remove a species before it becomes problematic.
Although such efforts are generally considered critical to controlling invasive species, discoveries are often too late, or funding is lacking to fight the invaders-the USDA has only about $1.5 million nationwide to support such efforts.
"We are going to learn an awful lot through this infestation," Kyde said. "This is going to be extremely valuable in formulating how people might handle the same kind of incident with other species."
It would also show that such efforts are worth the investment, Tasker said. "One of the difficulties is coming up with success stories that we can point to," he said.
For information about the wavyleaf basketgrass, including information about identification and reporting sightings, visit www.dnr.state.md.us/wildlife/wl_basketgrass.asp. Anyone interested in participating in eradication efforts can contact Marc Imlay at firstname.lastname@example.org or Kerrie Kyde at 410-260-8534, 1-877-620-8DNR x8367 (TTY users dial 711) or KKyde@dnr.state.md.us.
Wavyleaf basketgrass is a low-lying, trailing perennial grass. Its flat leaf blades are about 0.5- to 1-inch wide and 1.5 to 4 inches long and have elongated pointed tips. There are rippling waves across the deep green grass blades, as though the tide were coming into shore along the leaves.
The leaf sheaths and stems are noticeably hairy, although the hairs are very short.
When the plant blooms, from mid-September through November, the grass spikelets have glumes (lower bracts) with very long awns (extended pointed tips). The awns produce a sticky substance that allows the grass seed to adhere to and be dispersed by passing animals or the pants of humans. It also spreads by branching and rooting at nodes along creeping stems called stolons.